An easy method of making hamburgers having relatively uniform thickness and smooth consistency is desirable, and has been achieved by use of automatic machinery in certain commercial settings. For example, in Roth U.S. Pat. No. 4,192,899, a method for forming frozen meat patties is disclosed having a continuously rotating refrigerated drum which moves an extruded ground meat product, then compresses and cuts the extruded meat into patties. A plurality of reciprocating cutters forms several patties at one time, then the patties are slid onto a conveyor belt and carried away to a packaging station. The waste meat sections between the cut patties are dropped onto another conveyor belt which returns the waste meat to be re-ground for reprocessing in the system. It should be noted that the pneumatically operated cutter has a concave lower surface which includes vacuum breaking holes that allow any vacuum that may form between the lower surface of the cutter and the hamburger to be vented, in order to assist in releasing the hamburger from the cutter lower surface. Such holes would likely become clogged on a regular basis (due to meat product residue clinging to the lower surface and thereby covering the holes), and would require constant cleaning and maintenance in order to keep the holes and their associated air flow paths clean enough to be effective.
It is obvious that the complexity and size of the machinery required to implement Roth is much too great to use in the home. The Roth apparatus requires not only a special air vent, but it calls for the introduction of compressed air into the mold if the meat patty does not initially release from the mold. In addition, the purpose of Roth is to freeze the meat as the machinery is forming the patties. A person making a hamburger patty in the home would likely be as interested in making non-frozen patties (for immediate consumption) as in making frozen patties. It is, therefore, clear that the Roth patent will not meet the requirements of a household hamburger maker.
Other devices in the prior art are available that could be used in the home, including devices disclosed in Parker U.S. Pat. No. 2,008,725, Baker U.S. Pat. No. 2,082,080, Carpenter U.S. Pat. No. 3,045,277, Lee U.S. Pat. No. 28,106, and Robinson U.S. Pat. No. 3,863,020. In Parker, a culinary mold is disclosed having a hand- held ejector in the form of a cruciform grid, which impresses a pattern in the molded article (such as ground beef). The cruciform grid has members which are very thin and touch the molded article with just a small amount of surface area. The grid acts to disengage the article from the mold, and by virtue of its touching the article at only a small surface area, the grid also disengages itself from the article with ease.
The Baker patent discloses an open meat patty mold that uses no press at all. The ground meat is packed into the mold manually, and a knife is then used to cut off the top surface of the meat, thereby leaving behind a circular patty. To disengage the patty from the mold, the mold is either turned upside down, or a knife is used to pop the meat out of the mold. Baker's apparatus is clearly a crude device having simplicity as its chief advantage.
In Carpenter, a ground meat mold is disclosed having six circular receptacles. Ground meat is pressed into each of the circular receptacle by use of a hand-held circular tool which is used to press the meat downward into the receptacles. To disengage the patty from each of the molds, the entire apparatus is either turned upside down, or a knife is used to pop the meat out of each of the molds. Carpenter's apparatus is, thus, similar to the above Baker apparatus, with the additional advantage of the hand-held circular tool which is used to press the meat down into a more cohesive patty.
The Lee patent discloses a food patty press which includes a vertical passageway, a bottom closure plate, and a plunger that can be rocked slightly as it is pushed down while forming a patty. After the plunger forms a patty, the plunger can be pulled back out of the vertical passageway in order to place a separator disk on top of the existing patty. Another portion of food can then be placed on top of the separator disk, the plunger reinserted into the vertical passageway, and a second patty formed on top of the first patty. Several patties can be formed within the vertical passageway in this manner, each having a separator disk adjacent to its surface. Later, all patties can be removed by opening the bottom closure plate and pushing down the plunger until all the patties are pushed out of the vertical passageway.
In Robinson, a method of preparing a meat product is disclosed wherein meat is pressed into a mold which has concentric circular grooves in its upper and lower portions. The lower portion is in the shape of a circular mold. In order to use this apparatus, the mold upper and lower portions are separated in order to place a plastic wrapping material across the lower portion, and to insert a ground meat product into the lower portion. The upper portion is then closed, and a handle on the upper surface of the upper portion is rotated to produce an "ironing" action, which compacts the meat within the grooves of the inner surfaces of the upper and lower portions. The meat patty thus created is formed with concentric grooves in its top and bottom surfaces. The plastic wrapping material which was placed across the lower portion is then pulled up and out of the lower portion, thereby removing the meat patty from the mold.
None of the above devices for use in the home provide means for cleanly separating the meat patty from the mold while retaining a smooth surface for the meat patty. As was noted in Roth, above, some means for relieving any vacuum that might form between the molded meat patty and the mold surface is desirable, in order to achieve a clean separation of the meat patty from the molding apparatus. In Roth, vacuum breaking holes were provided, and compressed air could additionally be introduced through other holes, if necessary, in order to achieve the desired clean separation. A system such as Roth, however, as noted above, simply is not practical for use in the home.
One of the above devices for the home allows for a clean separation of the meat patty from the mold, but does not provide for a smooth patty surface. The Parker apparatus includes a cruciform grid made up of relatively thin elements which allow the existence of plenty of air space within the mold which eliminate the possibility of the forming of any vacuum that might cause the meat patty from failing to easily release from the mold. On the other hand, the meat patty produced by Parker would not be smooth, but would have the pattern of the cruciform grid impressed into its surface.
The other above devices for the home do not include means for insuring a clean separation of the meat patty from the mold. The Baker and Carpenter devices require gravity, possibly with the assistance of a knife to pry out the meat patty, to cause the meat patty to disengage from the mold. Unless the mold surfaces were made of a "no-stick" surface, which is not taught by these references, the meat patty will not come out of the mold having a smooth surface. The Lee apparatus may not require a knife in order to separate the meat patty from the mold, however, neither does it provide a means to eliminate any vacuum build up that would form between the plunger and the meat patty, or between a separator disk and the meat patty. In other words, Lee does not teach a means for insuring that the meat patty will have a smooth surface. Robinson teaches a method of making meat patties that have concentric circular grooves in their top and bottom surfaces, so it is evident that Robinson does not teach a means for insuring that a meat patty will have a smooth surface.
It is desirable to make meat patties that have smooth surfaces after they are formed in the mold. This desire is provided for in the industrial apparatus disclosed in Roth, but not in any of the above references that are suitable for use in the home.